Estudo experimental com heteroenxertos valvares descelularizados: a prótese do futuro

Abstract

Objective: To make a comparative evaluation of the behavior of cryopreserved homografts and decellularized porcine heterografts implanted in the right ventricular outflow tract of juvenile sheep as well as to report on the initial clinical experience with decellularized pulmonary homografts in patients submitted to the Ross procedure.Method: In group A, four cryopreserved homografts were implanted and in group B four heterografts decellularized with deoxycholic acid were used. In each group, two animals were sacrificed at 90 days and the other two at 150 days. The explants were evaluated macroscopically, and radiologically, as well as undergoing a histological examination with HE, Gomori and Sirius Red staining. We also report our initial clinical experience with decellularized pulmonary homografts in four patients submitted to the Ross procedure.Results: All the animals survived. Echocardiograms evidenced that all the implanted valves had normal function. Although the cusps had normal appearance in both groups, calcium content was higher in the cryopreserved valves, radiologically there were traces of calcification in the cryopreserved valves but no traces were observed in the decellularized valves. Cryopreserved homografts lost their cellularity while decellularized heterografts were progressively repopulated by fibroblasts and were partially re-endothelialized. Four patients submitted to a Ross operation with decellularized homografts had a good clinical outcome with normal function in their right-sided homografts.Conclusions: Decellularized heterografts were progressively repopulated by autologous cells and exhibited minimal tendency to calcification in this model. These results suggest that decellularized heterografts may have some regenerative capacity and thus potentially greater durability than conventional cryopreserved homografts. Descriptors: Homografts. Tissue engineering. Heart valve, surgery.DA COSTA, FDA ET AL -Experimental study with deccelularized porcine heterografts -the prosthesis of the future Bras Cir Cardiovasc 2004; 19(1): 74-82 DA COSTA, FDA ET AL -Experimental study with deccelularized porcine heterografts -the prosthesis of the future Bras Cir Cardiovasc 2004; 19(1): 74-82 Rev Rev

Avaliação do comportamento biológico de homoenxertos valvares pulmonares descelularizados: estudo experimental em ovinos

“…Described by O'Brien et al [1], cryopreservation allows longer storage of these grafts and, in some series, is associated with increased durability when compared with other preparation techniques [1]. Still, the grafts are not ideal because they are subject to progressive degeneration, especially in children and young adults [2][3][4][5]. …”

Efeito da criopreservação e/ou da descelularização na matriz extracelular de condutos valvados porcinos

“…Ideally, the decellularization technique should be able to completely remove all cells and cell debris and at the same time maintaining the integrity of the extracellular matrix. Our research group at the Center for Cardiovascular Grafts PUCPR tested several decellularizing solutions, and those showing the best results, DOA 1%, SDS 0.1% and SDS 0.3% [8,11,16,17,23,24], were selected for this study. On the other hand, the cryopreservation technique used here was similar to that used by the Banco de Valvas Cardíacas Humanas da Santa Casa de Curitiba [18].…”

Experiência inicial da utilização do xenoenxerto valvado porcino na via de saída do ventrículo direito em cardiopatias congênitas

“…Glutaraldehyde is utilized in its preparation and thus all the consequences of this, as previously mentioned, will be seen in the patient's evolution. Isolated decellularization of homografts is still in the initial phase of study, but this may be another option to minimize degeneration of this graft [6].…”